One rear seat backrest frame of this type is known from WO 01/89875 A1. It is comprised of several backrest frame elements, each of which is assembled in a modular fashion from specially designed modular components and standard modular components. The corner regions of each backrest frame component are formed by specially designed modular components, between which standard modular components, if necessary combined with specially designed modular components, are installed in a vertical orientation, and standard modular components are installed in a horizontal orientation. To construct a wider backrest frame component, a vertically extending center support is also provided, to which standard modular components are attached on both sides, extending in a transverse direction.
U.S. Pat. No. 6,260,924 B1 describes a modular rear bench-type seating system with two backrest frame elements, in each of which the back plate and the upper hat-shaped section or the upper cross member are designed to form a single piece. Vertically extending plates are also attached at the sides.
DE 101 42 981 A1 describes a backrest cushion support for a vehicle seat comprising a main plate and a reinforcement frame that partially encompasses the plate and is modular in design. In this case the essentially U-shaped reinforcement frame, which is open toward the base, is provided with intentional separation points, at which it can be partitioned and then reassembled in a different configuration. The lower regions of the outer vertical leg are provided as the separable section. To create a wider backrest frame component, a lower crossbar, and between the lower crossbar and the upper horizontal arm a vertical center rail can also be attached as reinforcement elements.
Modular systems of this type enable cost-effective production, as the backrest frames required for the various seats or seat types can be assembled from preset modules, if necessary by cutting them to size.
However known modular systems still require individual modules that are quite costly to produce, to some extent with complex shaped corner regions. In addition, the range of variants of backrest frame components that can be formed is limited; in particular, frequently only a single division of the rear bench-type seat is possible.
Furthermore, the attachment of the cushion and/or the cover requires additional mounting elements, which must be separately constructed or attached. Thus to some extent quite complex shapings and tools that must be specially designed for this purpose are necessary, as the width of backrest components varies—especially in the case of an asymmetrical partitioning of the rear bench-type seat or with different types of vehicles.